The defeat of Richard Lugar in Indiana’s primary Tuesday is not just a defeat for moderation in the Republican party. It’s also a loss for that quality we at one time liked in our leaders — hard-earned expertise; and for that skill we all believe we need more of — leadership.

Lugar, the six-term Hoosier senator, lost the primary on Tuesday to Richard Mourdock, Indiana’s state treasurer, who captured 60 percent of the vote. Backed by the Tea Party, Mourdock is a former geologist who has held seats on county commission boards and been state treasurer since 2006. He has been running campaigns since his first election in 1988, so he is no “Christine O’Donnell in a necktie,” as the New York Times called him. He may be most known for his efforts to stop the auto bailout as state treasurer of Indiana.

Meanwhile, Lugar was the Senate’s top expert on nuclear arms proliferation. He was the ranking member of the Senate Committee on Foreign Relations and had served as its chairman more than once. Washington Post columnist Dana Milbank provides a rundown of his many admirable accomplishments: securing sanctions to end South African apartheid, bringing democracy to the Philippines, and drafting legislation that disarmed thousands of Soviet nuclear warheads.

Even if some could attribute his loss to the fact that he is 80, out of touch with his constituents in Indiana, or didn’t do enough to run a modern campaign, Lugar is an unquestioned expert on a topic that remains of supreme importance even in today’s post-Cold War era. Voters seem to care less about that, however, preferring candidates whose most notable expertise tends toward making their platform as pure as possible in the eyes of their party.

“This is a historic time,” the Times quotes Mourdock as saying, “and the most powerful people in both parties are so opposed to one another that one side simply has to win out over the other.” The problem in Washington, he has reportedly said, “is too much bipartisanship.”

In other words, at least by those quotes, Mourdock seems to believe that the leaders we need are not those who can heal division or bring the two parties together, but those who can force their beliefs onto the rest by winning in greater numbers. That’s not leadership, that’s domination. By losing the middle on both sides of the aisle, we’re not just setting up a system that results in more divisive politics and extreme policies, but a landscape that makes it all but impossible to actually lead.

Rebuilding the expertise Lugar had in foreign policy will not be easy, especially if voting out so-called “Washington insiders” remains more important to voters than retaining institutional knowledge. But what will be even more difficult if lawmakers like Lugar are replaced by unyielding partisans on either side (Mourdock still has to face the Democratic candidate, Joe Donnelly) is for anyone — any committee chairman, any Senate Majority Leader or any president — to find a way to lead them.

Even worse, it could dissuade more young people of either political stripe who have an interest in bringing people together to enter public service. As Indiana University’s Public Policy Institute director John Krauss lamented to the Indianapolis Star, “When you see a visionary and consensus-builder such as Lugar fail in a re-election bid, it may discourage people with similar skills from seeking office. We need to inspire and encourage young leaders, not disillusion them. We desperately need them.”

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